This invention relates to a process for making foods and feeds out of raw material such as flour, meal and grits of cereals, pulses, starch roots, tubers, oil seeds, cakes of oil seeds, milk products and mixtures of these materials.
Starting with these raw materials it is possible to obtain foods or feeds having a high nutritive value and good protein contents. The essential aminoacids in the resulting products are sufficient, or at least it is not necessary to supplement them in too large a measure.
As these raw materials are generally obtainable locally, even in countries where there is a problem of insufficient nutrition, and as their price is not too high on the average, the resulting products are particularly useful in developing countries. No limitation of utilization in any particular country is to be construed from this statement, as it will be shown below that products obtained by the new process can fulfill as high a standard of quality as may be set reasonably in any country.
A process for making foods and feeds from the above-mentioned raw materials already exists which uses a plant similar to that utilized generally for the production of short-cut macaroni products. Between the extrusion press and the continuous belt driers a continuous immersion device and a continuous cooking apparatus have been provided. When the process is used in the manufacture of weaning flours, the raw materials are mixed, extruded, showered with water, cooked for about 5 - 10 minutes by means of steam, and then dried to 6 - 8% water contents. Owing to the cooking step, the drying time is only about 2 hours, for example, much less than for conventional macaroni products. The dried product is then comminuted to a flour and stored in storage elements. Before packaging, the product is extracted from the storage elements and mixed with suitable complements, such as aminoacids, vitamins, mineral salts, concentrated proteins, sugar and aromas. It is also possible to add raw sugar, yeast, milk powder at the mixing stage, obtaining thereby a sterilization of these materials. On the other hand, if the supplemental products are added before packaging, the capacity of the manufacturing line is higher and the vitamins and aminoacids do not undergo a degradation. The chief advantage of the above-outlined process is due to the fact that it is possible to provide alternate equipment between the press and the drier, for example, a conventional pre-drier with vibrating conveyors, such as is in extensive use throughout the world for the manufacture of short-cut macaroni products. When the plant is not in use for the production of weaning flour, it is used for the manufacture of conventional short-cut macaroni products.
Considering further the production of weaning flours, another development has been based on the following considerations: The major food of the world is starch, for those foods which form the mainstay of human diet are all rich in starch. But starch is too difficult to digest for the stomach of children at weaning (6 months to 2 years).
As is well known, the first step in the hydrolysis of starch is the formation of dextrins. This reaction leads to a series of polymer fragments of varying molecular size. Dextrins are a mixture of soluble compounds formed by the partial breakdown of starch.
One of the most important intermediate stages during the breakdown of starch to glucose in maltose. It has 33% of the sweetness of sucrose and is formed by two molecules of glucose.
Glucose (or dextrose) is the major product of the digestion of carbohydrates in the intestines and is the form in which the carbohydrate is absorbed into the bloodstream. It is less sweet than sucrose (74% of the sweetness of sucrose).
With these considerations in mind, the flours of cereals and the like have been mixed with water and heat-resistant .alpha.-amylase. These have then been preheated in a steam-jacketed agitating tank, dried over a double rotating drum-drier and packaged after blending with supplemental products similar to those of the preceding example. Because of the enzymatic conversion of starch into dextrins and sugars, the digestibility coefficient of the product reached very high levels and its organoleptic characteristics were much improved. Before packaging it, much less sugar must be added. The viscosity of this product was very low, making it possible for children to absorb the flour without an unduly high addition of water. A disadvantage resided in the relatively high costs of the manufacturing plant which furthermore cannot readily be used for other types of production. As the working temperature must be relatively high, namely 140.degree.C (284.degree.F) or at least 130.degree.C (266.degree.F) for obtaining a sufficient throughput, some essential aminoacids, particularly lysine, are destroyed. Furthermore, the caloric consumption is much higher: 2.6 to 4 kg heating steam per kg of finished product is needed, against 1 kg heating steam per kg of finished product in the case of the process carried out with the macaroni manufacturing line.